Disk brake fluid inlet and bleeding arrangement



Dec. 14, 1965 R. T. BURNETT ETAL. 3,223,207

DISK BRAKE FLUID INLET AND BLEEDING ARRANGEMENT 2 Sheets-Sheet 1Original Filed Nov. 21, 1960 VE 0 2/01/ 220 7. Bu- IA/ 155 J. PowL/isATTORNEY Dec. 14, 1965 R. T. BURNETT ETAL DISK BRAKE FLUID INLET ANDBLEEDING ARRANGEMENT Original Filed Nov. 21. 1960 2 Sheets-Sheet 2VENTORS 1N E/cWA/ED TBUENETT 7' TOENE Y United States Patent 3,223,207DISK BRAKE FLUID INLET AND BLEEDING ARRANGEMENT Richard T. Burnett andJames I. Powlas, South Bend, Ind., assiguors to The Bendix Corporation,South Bend, Inch, a corporation of Delaware Original application Nov.21, 196i}, Ser. No. 70,640, new Patent No. 3,166,156, dated Jan. 19,1965. Divided and this application Nov. 30, 1964, Ser. No. 414,704 4Claims. (Cl. 188152) This application is a division of our co-pendingapplication Serial No. 70,640, filed on November 21, 1960, now PatentNo. 3,166,156.

This invention concerns a disk brake hydraulic motor which includes anautomatic adjuster for adjusting the released position of an actuatingpiston.

The main object of this invention is to ensure complete bleeding of airfrom the hydraulic motor when it is filled with brake fluid.

Other objects will become apparent to those skilled in the art from thefollowing description with reference to the drawings wherein:

FIGURE 1 is a side elevational view of the brake as it is installed onthe right front vehicle wheel, with a portion of the rotor broken away;

FIGURE 2 is a sectional view taken on line 2-2 of FIGURE 1; and

FIGURE 3 shows the outboard side of the brake or the side of the brakeopposite that shown in FIGURE 1.

Referring now to the drawings, there is illustrated a brake rotor havingannular, oppositely-facing braking surfaces 12 and 14 which make up therotatable part of the brake structure. The rotor is fastened in someconvenient manner at its radially inner portion to a rotatable part ofthe vehicle such as an axle flange (not shown).

The nonrotatabie part of the brake structure comprises a mounting member16 having at its radially inner ends 18 portions adapted for mountin ona fixed part of the brake such as an axle housing or the like (notshown). The mounting member provides two edge faces 21 and 23 which formanchoring surfaces for the brake.

There is mounted on member 16 a four sided cage structure which movesslidably on anchoring surfaces 21 and 23 but is prevented from rotatingcircumferentially by said surfaces 21 and 23, the cage being made up of:two spaced brackets 25), 22 which straddle the outer periphery of themotor and are guided by engagement with lugs 24, 26 of the member 16; afluid motor housing 23 having bolt connections 30 with the brackets 20,22; and a friction member 32 which is fixed to the brackets at theoutboard side of the brake together with a bolt 36 which fastens to thebrackets 20, 22 through rubber washers or the like 38 that deadenvibration conducive to brake noise. To further reduce brake noise, thereis a resilient spring 87 between each bracket 29, 22 and its anchoringsurface 21, 23 of the mounting member 16 to cushion the anchoring loadand prevent rattles and similar brake noises. The cage structure is freeto move pivotally on lugs 24, 26 in a plane transversely to the rotor 16thereby enabling the friction members 32, 34 on each side of the rotorto conform with their opposed rotor surfaces. The described movement ofthe cage is permitted because the cross section of the lugs is narrowrelative to the slots 35, 39 which are the supporting means between thecage and mounting member 16. Moreover, the cage is free to pivot in theplane and in the direction indicated by the arrows in FIGURE 2. In thisinstance the cage moves at one or the other of the anchoring edges 21 or23 of the mounting member 16, also contributing to freedom of movementof the friction members 32, 34 so that they will conform to the opposingrotor surfaces in spite of deflections thereof.

The outboard friction member 32 comprises a backing 37 having spacedsegments of friction material 38 and 40. The other friction member 34,which is at the inboard side of the brake includes a backing 48 havingturned back flanges 50 and 52 at its opposite ends and additionalflanges 54, 56 also located at the ends of the frction member to fitslidably within slots 35 and 39 of the brackets 20, 22 thereby guidingthe friction member 34 in its lateral movement toward and away from theface 12 of the rotor 10. The flanges 5t), 52 bear against the innerfaces 60 and 62 of the brackets 20, 22 respectively, transmitting theanchoring force of friction member 34 to one or the other bracketdepending upon the direction of rotor rotation during braking operation.

Within the fluid motor housing 28 is a fluid pressure responsive piston64 having an O-ring seal 66 and a rubber or the like sealing boot 68which protects against entry of dirt within the power chamber 70. Alsowithin the fluid motor housing is an automatic adjuster 72 which doesnot form a part of the present invention and is disclosed in detail inUS. Patent No. 3,134,459, previously filed by us. In brief, theautomatic adjuster serves to locate the piston 64 more closely to therotor as the friction segments become worn in order to maintain a properrunning clearance in the brake between the friction members and theopposed rotor surfaces and also to effect retraction of the piston by afixed amount following each brake application by a retracting spring 74.Details of the structure may be had by reference to the aforesaid US.Patent No. 3,134,459.

The invention concerns a novel provision for fluid inlet and bleeding offluid from the housing 28. The novel inlet means comprises a port 76connecting with passage 79, longitudinal passage 78 in stem 86 whichterminates in chamber 81, there being a number of grooves 83 throughwhich the fluid then passes to the power chamber 70 where is can be bledfrom bleeder port 85. Due to this arrangement, fluid will have to passthrough the chamber 81 prior to entering the power chamber 79, thusforcing any air in chamber 81 out of chamber 81 into the power chamber70 and out the bleeder port 85. If a conventional inlet system wereused, wherein the inlet passage 79 communicates directly with the powerchamber, fluid will tend to pass directly through the power chamber tothe bleeder port 35 without necessarily forcing air out of the chamber81. In other words, air is likely to be trapped in the chamber 81 when aconventional system is used, while complete removal of air from chamber81 is ensured by the novel arrangement disclosed herein.

In operation, the brake is applied by communicating fluid pressure toinlet 76 through passage 78 of the stem and into chamber 70 thuseffecting displacement of piston 64 toward the left (FIGURE 2) causingthe friction member 34, which is in abutment with the end of the piston64, to move toward the left thereby engaging friction material lining 82with surface 12 of the rotor 19. The piston extends through an opening86 of the support member to be in direct engagement with the frictionmember 34. The fluid pressure simultaneously urges the housing 28 towardthe right (FIGURE 2) thereby drawing the brackets 20, 22 toward theright which slide at notches 35, 39 on lugs 24, 26 of the mountingmember 16. The brackets movement as described draws friction member 32toward the surface 14 of the rotor thereby engaging friction segments 49against the surface 14 of the rotor 10.

While the embodiments of the invention as herein disclosed constitutes apreferred form, it is to be understood that other forms may be adopted,all coming within the scope of the claims which follow.

We claim:

1. In a brake: a cylinder housing having a bore closed at the rear endthereof, and open at the front end thereof, a piston slidable in saidbore, a recess in said piston open at the rear end thereof, said recessand said bore together defining a fluid chamber, a member secured at therear end thereof to said closed end of said bore and extending forwardlytherefrom into said recess, automatic adjusting means surrounding saidmember and operatively connected thereto and to said piston foradjusting the released position of said piston, said automatic adjustingmeans separating said fluid chamber into a front portion which isentirely within said piston recess and a rearward porinto said frontportion of said fluid chamber.

2. The structure as recited in claim 1 wherein said first named passagemeans comprises a portion of said adjusting means.

3. The structure as recited in claim 1 wherein said member is elongated,said last named passage means includes a longitudinal bore in saidelongated member communicating with that portion of said last namedpassage means in the closed end of said cylinder bore.

4. The structure as recited in claim 1 wherein at least one groove is inthe wall of said recess, said adjusting means comprises an annularelement gripping said wall with a portion thereof bridging said groove,said first named passage means comprising said portion of said annularelement and said grove.

No references cited.

ARTHUR L. LAPOINT, Primary Examiner.

1. IN A BRAKE: A CYLINDER HOUSING HAVING A BORE CLOSED AT THE REAR ENDTHEREOF, AND OPEN AT THE FRONT END THEREOF, A PISTON SLIDABLE IN SAIDBORE, A RECESS IN SAID PISTON OPEN AT THE REAR END THEREOF, SAID RECESSAND SAID BORE TOGETHER DEFINING A FLUID CHAMBER, A MEMBER SECURED AT THEREAR END THEREOF TO SAID CLOSED END OF SAID BORE AND EXTENDING FORWARDLYTHEREFROM INTO SAID RECESS, AUTOMATIC ADJUSTING MEANS SURROUNDING SAIDMEMBER AND OPERATIVELY CONNECTED THERETO AND TO SAID PISTON FORADJUSTING THE RELEASED POSITION OF SAID PISTON, SAID AUTOMATIC ADJUSTINGMEANS SEPARATING SAID FLUID CHAMBER INTO A FRONT PORTION WHICH ISENTIRELY WITHIN SAID PISTON RECESS AND A REARWARD PORTION, PASSAGE MEANSCOMMUNICATING SAID FRONT PORTION OF SAID FLUID CHAMBER WITH SAID REARPORTION OF SAID FLUID CHAMBER, AND FLUID INLET PASSAGE MEANS LOCATED INTHE CLOSED END OF SAID BORE AND WITHIN SAID MEMBER OPENING INTO SAIDFRONT PORTION OF SAID FLUID CHAMBER.